Trim tensioning limiter

ABSTRACT

Apparatus for conveying continuous web edge trim under tension, with means for severing such trim when it is subjected to longitudinal tensions above a predetermined value to thereby prevent the travel of excessive tensions back to locations at which web trimming is being effected.

UNITED STATES PATENTS United States Patent [1 1 1111 3,731,570 Nelson 11 May 8, 1973 [54] TRIM TENSIONING LIMITER 2,609,875 9 1952 Zuck..83/579 1,419,302 6/1922 Pape ...83/370 X Inventori Seddon Nelson,Frederwksburg, 1,397,911 11/1931 Tossi'zza ..83/370 Va. 1,369,853 3/1921Tetetleni ..83/579 [73] Ass1gnee: FMC Corporation, Ph1lade1ph1a, Pa.Primary Examiner Andrew R. Juhasz [22] Filed: Oct. 4, 1971 AssistantExaminer-Leon Gilden Att Th R.OM 11 11 1. 21 Appl. No.: 185,961 omas aeye a [57] ABSTRACT [52] U.S.CI. ..83/370, 83/359,83/579, Apparatus forconveying continuous web g trim 83/923 under tension, with means forsevering such trim when [51] Int. Cl. ..B26d 5/38 it is ubjected tolongitudinal tensions above a [58] Field Of Search ..83/370, 359, 923,predetermined value to thereby prevent the travel of 83/112,161,579excessive tensions back to locations at which web trimming is beingeffected. [56] References Cited 11) Claims, 6 Drawing Figures PAIENIED M191s SHEET 1 OF 2 PATENTEB HAY 81975 SHEET 2 OF 2 TRIM TENSIONINGLIMITER The present invention is directed to conveying, under tension,edge trim slit from continuous webs, and particularly to an apparatusfor isolating the locations of web slitting from excessive tensionsapplied to the trim itself.

In typical web slitting operations, edge trim removed from individualwebs by each of a number of separate slitters is combined togethercontinuously and concomitantly with its formation and is conveyed to asuitable collection station. Conveyance of such combined mass of webedge trim is generally achieved by delivering air under pressure througha header into which open ducts leading from each of the separate webslitters. At the respective slitters the individual ducts themselves arebifurcated to provide branches having venturi suction inlets which arepositioned at the locations of web slitting to receive edge trimimmediately after it is formed.

Excessive tension applied to edge trim is transmitted back to slittinglocations at which such trim is formed and generally results in at leasta break in the continuity of the trim itself. As a more concreteexample, web slitters supplying edge trim to a common discharge headerare often operated at different speeds, with the speed of each slitterbeing dictated, for example, by the particular type or characteristicsof the web being slit or its roll formation. Under such operatingconditions, edge trim formed by the separate web slitters will traveltoward and into the discharge header at different rates. It has beendiscovered that within the discharge header itself the more rapidlyadvancing edge trim tends to bundle or warp itself about the slowertraveling edge trim. This bundling of edge trim may accelerate theslower moving trim. However, a more serious consequence is that thebundled trim acts as a plug which assumes an intermittent movement as itis propelled by the air flowing through the discharge header. Theerratic pulsating movement of the bundled trim is transmitted totrailing portions of the edge trim and, much too often, subjects theslower moving edge trim to such tensions as to rupture the same atlocations of web slitting.

Once such break occurs at a web slitting site, the edge trim whichcontinues to be formed at such location tends to wrap itself about thedifferent pull and idler rolls of the slitter and/or cause the slit webto break, and/or be trapped inbetween overlying layers of slit webduring its winding into rolls. Correction of these difficulties can beachieved only by stopping operation of the slitter to removed edge trimfrom slitter rolls and/or splice ruptured web ends. Such clean-upmeasures, however, are costly, often resulting in damage to the slitterrolls, waste of materials and, if

web splicing is necessary, providing an inferior end.

product. Accordingly, a primary object of this invention is to provide agenerally new or improved and more satisfactory apparatus for conveyingedge trim from a web slitter.

Another object is the provision of improved apparatus for moreefficiently removing edge trim from web slitters which are operated atdifferent speeds.

Still another object is to provide an apparatus for conveying edge trimfrom a web splitter under longitudinal tension, with the web slitteritself being isolated from excessive tensions which may be applied toedge trim during its conveyance.

A further object is the provision of an apparatus in which edge trimslit from a continuous web is subjected to longitudinal tension toconvey the same and is automatically severed when the longitudinaltension applied thereto exceeds a predetermined level.

A still further object of this invention is to provide apparatus for usein a system in which web edge trim is conveyed under longitudinaltension simultaneously from a plurality of web slitters operating atdifferent speeds, with such apparatus automatically regulating thedegree of tension exerted upon the edge trim at individual locations ofweb slitting.

These and other objects of the invention are achieved by an apparatusfor conveying continuous edge trim away from a web slitter underlongitudinal tension applied thereto, with the web slitter beingisolated from such tensions exerted on the edge trim as might cause thecontinuous trim to break at a location of slitting.

As in conventional trim removal systems, web edge trim is advanced toand beyond the apparatus of the present invention through a duct which,together with other similar ducts from other individual web slitters,opens into a common header. A fluid, such as air, is caused to flowthrough this common header, creating a suction effect at the inlets ofthe individual ducts, and conveying the edge trim which is within suchheader to a suitable collection site. Preferably, each of the individualducts of such trim removal system is equipped with the apparatus of thepresent invention. However, for the sake of clarity and simplicity theapparatus of the present invention is hereafter described asincorporated into only one of such ducts.

More particularly, the apparatus includes a cylinder which is disposedalong the path of trim advancement through a duct and about theperiphery of which the trim is adapted to be looped. This cylinder issupported for rotation about its longitudinal axis under torque appliedthereto by the tensioned trim as it is advanced over the cylinderperiphery. Included also in the apparatus are means for resistingcylinder rotation when the tension on the edge trim beyond the cylinderexerts thereon a torque less than a predetermined value. Operativelyconnected with the cylinder is a cutting blade which is projected acrossthe path of and severs the web edge trim looped about the cylinderperiphery when the cylinder is rotated under a torque at least equal toa predetermined value.

A baffle within the trim-conveying duct, together with adjacent walls ofsuch duct, cooperate with the cylinder to define a helical passage aboutits periphery whereby edge trim is looped about the cylinder peripheryduring its advancement through the duct.

The cutting blade employed in; the apparatus of the present invention issupported within the cylinder for pivotal movement about an axissubstantially parallel to that of the cylinder. A slot, extendingsubstantially parallel to the cylinder axis, opens along the cylinderperiphery and it is through this slot that the cutting blade isprojected when the cylinder is rotated. Blade projection is preferablyachieved by a plate cam which is fixed to the cylinder at substantiallyright angles to its axis and includes a cam surface for urging thebladeabout its pivot axis when the cylinder is turned.

Cylinder rotation, and thus blade projection, is effected when thetension exerted on the web edge trim beyond the cylinder; that is,downstream from the cylinder, subjects such cylinder to a torque atleast equal to a predetermined value. Upon projection of the cuttingblade, the edge trim looped about the cylinder periphery is severed. Theweb edge trim and slitter located upstream from the cylinder are therebyisolated from tensions which may well have caused such trim to break atlocations of web slitting. Since severance of the edge trim, asdescribed, occurs on the cylinder itself, no difficulties areexperienced by the newlyformed leading end of the edge trim in lacingitself through the portion of the duct beyond the cylinder.

With the apparatus of the present invention, tensions exerted on theadvancing edge trim which normally have no significant affect on webslitting operations are permitted to travel back to the web slittinglocations. Such tensions may apply torques to the cylinder which willtend to rotate the same. Under these conditions, however, cylinderrotation is resisted by a counteracting moment as provided by a tensionspring or weight acting on the free end of a lever arm which is fixed tothe cylinder itself.

The apparatus of the present invention is adapted for use with a varietyof flexible web materials, as for example, films formed of thermoplasticmaterials, cellulose films, such as paper and cellophane, fabrics, etc.

In the drawing,

FIG. 1 is a,perspective view diagrammatically illustrating the useof theapparatus of the present invention during web slitting operations;

FIG. 2 is a side view of the apparatus of the present invention, with aportion thereof removed;

FIG. 3 is a vertical section taken through the apparatus shown in FIG. 2substantially along the lines III-' --III;

FIG. 4 is a perspective view of the apparatus shown in FIG. 2;

FIG. 5 is a view similar to FIG. 4 with portions of the apparatus beingremoved to show the interior construction thereof; and

FIG. 6 is broken plan view of the apparatus shown in FIG. 2. v

Illustrated in FIG. 1 is a typical web slitting operation wherein acontinuous web 11 is drawn from a mill or supply roll, passed overspaced guide rolls 13 and 15, and, during such passage, slit by fixedblade, such as indicated at 17, to remove irregular edge portions 19 and21. Concomitantly with the edge slitting, the web 11 may also be slitinto a number of separate webs, as shown at 23 and 25, which aretransferred by a roll 27 to cores 29 and 31 and wound into rolls.

The edge portions 19 and 21 trimmed from web 11 are laced over a guideroll 33 and passed into branches 35 of a duct 37 which opens into aheader 39. Air is caused to flow through the header 39, as indicated at41, creating a venturi effect at the entrances of the branches 35 of theduct 37 which assists in drawing the edge trim 19 and 21 therein. Edgetrim from other web slitters, not shown, is also delivered into theheader 39 by separate ducts 43 and, together with the edge trim from theduct 37, is conveyed through such header to a suitable collectionstation.

As best seen in FIGS. 2 and 4, the duct 37 includes inlet and outletsections 45 and 47 which are arranged with adjacent ends thereof inside-by-side relationship along the length of a cylinder 49. The ductsection 45 is generally rectangular in cross-section and includes a pairof opposing walls 51 and 53 which are disposed in convergingrelationship adjacent to the cylinder 49 to insure smooth edge trimdelivery yet minimize fabrication costs. An arcuate wall 55 extends fromthe wall 51, in spaced and generally concentric relationship with thecylinder 49, and is fixed at 57 the wall 53, as by welding. A muchshorter arcuate wall 59 projects from the wall 53 with its free end 61located adjacent to and along a plane extending generally tangent totheperiphery of the cylinder 49.

The duct section 47 is also of rectangular cross-section and includesopposing walls 63 and 65 An arcuate wall 67 extends from the wall 63, inspaced and concentric relationship with the cylinder 49, and is fixed tothe opposing wall 65. The wall 65, on the other hand, extends beyond thearcuate wall 67 and terminates with a lip 69 which is flexed toward theperiphery of the cylinder 49, as best shown in FIG. 2.

As best seen in FIG. 3, opposing walls 71 and 73 of the duct section 45terminate substantially along a plane passing through the axis of thecylinder 49, while ends of corresponding walls 75 and 77 of the ductsection 47 are spaced from such plane. The arcuate walls 55 and 67 areof like radius and are connected to each other at 79 and, to the ductsection walls 75 and 71, respectively, at 81 and 83. The arcuate walls55 and 67 may, of course, be made from a single piece of materi-' al.Projecting from the arcuate walls 55 and 67 are flanges 85 to which aresecured end plates .87 and 89.

Fixed within and at substantially right angles to the axis of thecylinder 49 are a pair of plates 91 which, in turn, are keyedv at 93 toa shaft 95. As shown in FIG. 6, the ends of the shaft 95 extend throughsuitable openings in the end plates 87 and 89 which will permit suchshaft to rotate freely; that is, with no binding thereof. I

Portions of the plates 91 have been removed or cut away as indicated at97 to provide abutment and camming surfaces 99 and 101, respectively.Extending through these cut-away portions 97 of the plates 91 is a shaft103 which, like the cylinder shaft 95, is supported by the end plates 87and 89 for free rotary movement. A lever arm 105 is keyed at 107 to thecylinder shaft 95 and is urged in a counterclockwise direction, asviewed in FIG. 2. by a tension spring 109. The force exerted by thespring 109 serves to maintain the cylinder 49 in a position in which theabutment surfaces 99 of the plates 91 rest against the shaft 103.

Welded or otherwise fixed to the shaft 103 is a plate 111 to which issecured a cuttingblade 113. The cylinder 49 is sloted at to permit thecutting blade 113 to be projected from within the cylinder and beyondits periphery. As will be more apparent hereafter, projection of theblade 113 is achieved by rotating the cylinder clockwise, as viewed inFIGS. 2, 4 and 5, whereby the camming surfaces 101 on the plates 91 urgethe blade 113 about the axis of the shaft 103 and ultimately into aposition as shown by broken lines in FIG. 2.

As heretofore mentioned, the edge trim 19 and 21 from the web 11 iscombined within the duct 37 as indicated at 117 in FIG. 5 and, afterpassage through the duct inlet sections 45 and over the arcuate wall 59,is laced helically about the periphery of the cylinder 49 and into theduct outlet section 47.

Helical passage of the edge trim 117 about that portion of the cylinder49 which is aligned with the inlet section 45 is encouraged by a baffle119, the end portions 121 and 123 of which bear against the wall 71 ofthe duct inlet section 45 and the end plate 87, respectively. The outerperiphery of the baffle 119 engages with the inside surface of thearcuate wall 55, while its inner periphery is spaced from the peripheryof the cylinder 49 to avoid binding with the cylinder during itsrotation As best seen in FIG. 2 the inner periphery of that portion ofthe baffle 119 which extends between the cylinder slot 115 and the wall71 of the duct inlet section 45 is substantially concentric with theshaft 103 to facilitate the projection of the blade 113 during clockwiserotation of the cylinder. Any tendency for the edge trim 117 to wedge inbetween the end wall 89 and the end of the cylinder adjacent thereto isminimized by a collar 125 which is fixed to such end wall and encirclesthe cylinder 49. The inner surface of the collar 125. is spaced from thecylinder periphery to permit the cylinder to rotate without binding.

As heretofore mentioned, the apparatus of the present invention isintended to isolate a web slitter from tensions which, when applied tothe edge trim being conveyed, ordinarily cause such edge trim to breakat one or more locations of web slitting. Such excessive tensions mayarise beyond or downstream from the cylinder 49 as a result of bundlingof trim within the header 39, as previously described. In the absence ofexcessive tensions, the mass of continuous edge trim travels smoothlythrough the header 39 and the cylinder 49 will assume a position asillustrated in FIGS. 2--5, wherein the abutment surfaces 99 of theplates 91 are engaged with the shaft 103 and the blade 1 13 is fullyretracted within such cylinder.

When tensioned beyond the cylinder 49, the edge trim 117 applies to suchcylinder a torque which tends to rotate the same in a clockwisedirection, as viewed in FIGS. 1, 2, 4 and 5. Cylinder rotation isresisted by the force applied by the spring 109 and obviously, itstension force must be such as to counterbalance that torq'ue, less thana predetermined value, to which the cylinder 49 may be subjected. Oncethe countermoment provided by the spring 109 is overcome, the cylinder49 together with its shaft 95 rotates clockwise, urging the cammingsurfaces 101 of the plates 91 against the blade 113 andcausing suchblade to project beyond the cylinder periphery and through the edge trim117 which is in the path of such blade. The camming surfaces 101 areshaped to effect projection of the blade 113 during rotation of thecylinder 49 through an arc of about 60. Before this occurs, the ten sionapplied to the edge trim 117 beyond the cylinder 49 will be reduced byfriction between the trim and cylinder, thus isolating the slitter fromsuch smaller tension peaks without severing of the edge trim 117.

Once severed, the edge trim l 17 beyond the cylinder 49, moves freelythrough the duct section 47 and header 39, the cylinder 49 returns toits position as shown in FIGS. 2-5 with the blade 1 13 being retracted,and the newly formed leading end of the edge trim l 17 laces itselfthrough the duct outlet section 47.

It is to be understood that changes and variations may be made withoutdeparting from the spirit and scope of the present invention as definedin the appended claims. I I

Iclaim:

1. Apparatus for conveying edge trim from a web slitterincluding meansfor advancing continuous web edge trim under longitudinal tensionconcomitantly as it is slit from a web, a cylinder disposed along a pathof trim advancement and about the periphery of which such trim isadapted to be looped, means supporting said cylinder for rotation about.its longitudinal axis under torque applied by the tensioned edge trim asit is advanced thereover, means for resisting rotation of said cylinderwhen the tension on the edge trim beyond said cylinder exerts on suchcylinder a torque of less than a predetermined value, a cutting blade,and means car ried by said cylinder for projecting said cutting bladeacross the path of and severing the web edge trim looped about thecylinder periphery when said cylinder is rotated under a torque at leastequal to such predetermined value.

2. Apparatus as defined in claim 1 wherein said cylinder includes a slotopening along its periphery and extending substantially parallel to thecylinder axis, and pivot means for supporting said cutting blade withinsaid cylinder for movement about an axis substantially parallel to saidcylinder. 1

3. Apparatus as defined in claim 2 wherein said blade projecting meansincludes a cam fixed within said cylinder for urging said cutting bladeabout its pivot axis when said cylinder is rotatedto thereby project thecutting edge of said blade beyond the periphery" of said cylinder. r

4. Apparatus as defined in claim 3 wherein said cam is a platepositioned within and fixed to said cylinder at substantially rightangles to its axis of rotation, said plate having a surface which isadapted to rest against the cutting blade pivot means in the absence oftorque application to said cylinder, and a cam ming surface whichengages with said cutting blade ata location spaced from its pivot axiswhen said cylinder is rotated.

5. Apparatus as defined in claim 1 wherein said mean for resistingcylinder rotation includes a'lever arm fixed at one end to rotate withsaid cylinder, and'a spring extending between a fixed structure and thefree end of said lever arm for applying a force to saidcylinder which isslightly less than and counter to the torque of predetermined value. j

6. Apparatus as defined in claim 3 wherein said means for resistingcylinder rotation includes a lever arm fixed at one end to rotate withsaid cylinder,and a 9. Apparatus as defined in claim 3 wherein said camis shaped to effect projection of said cutting blade during a rotationof the cylinder through an angle of about 60.

10. Apparatus as defined in claim 5 wherein said cam is shaped to effectprojection of said cutting blade during a rotation of the cylinderthrough an angle of about 60.

1. Apparatus for conveying edge trim from a web slitter including meansfor advancing continuous web edge trim under longitudinal tensionconcomitantly as it is slit from a web, a cylinder disposed along a pathof trim advancement and about the periphery of which such trim isadapted to be looped, means supporting said cylinder for rotation aboutits longitudinal axis under torque applied by the tensioned edge trim asit is advanced thereover, means for resisting rotation of said cylinderwhen the tension on the edge trim beyond said cylinder exerts on suchcylinder a torque of less than a predetermined value, a cutting blade,and means carried by said cylinder for projecting said cutting bladeacross the path of and severing the web edge trim looped about thecylinder periphery when said cylinder is rotated under a torque at leastequal to such predetermined value.
 2. Apparatus as defined in claim 1wherein said cylinder includes a slot opening along its periphery andextending substantially parallel to the cylinder axis, and pivot meansfor supporting said cutting blade within said cylinder for movementabout an axis substantially parallel to said cylinder.
 3. Apparatus asdefined in claim 2 wherein said blade projecting means includes a camfixed within said cylinder for urging said cutting blade about its pivotaxis when said cylinder is rotated to thereby project the cutting edgeof said blade beyond the periphery of said cylinder.
 4. Apparatus asdefined in claim 3 wherein said cam is a plate positioned within andfixed to said cylinder at substantially right angles to its axis ofrotation, said plate having a surface which is adapted to rest againstthe cutting blade pivot means in the absence of torque application tosaid cylinder, and a camming surface which engages with said cuttingblade at a location spaced from its pivot axis when said cylinder isrotated.
 5. Apparatus as defined in claim 1 wherein said mean forresisting cylinder rotation includes a lever arm fixed at one end torotate with said cylinder, and a spring extending betweeN a fixedstructure and the free end of said lever arm for applying a force tosaid cylinder which is slightly less than and counter to the torque ofpredetermined value.
 6. Apparatus as defined in claim 3 wherein saidmeans for resisting cylinder rotation includes a lever arm fixed at oneend to rotate with said cylinder, and a spring extending between a fixedstructure and the free end of said lever arm for applying a force tosaid cylinder which is slightly less than and counter to the torque ofpredetermined value.
 7. Apparatus as defined in claim 3 wherein said webedge trim advancing means includes walls defining a duct within andacross which said cylinder is disposed, a fixed baffle within said ductcooperating with walls of said duct and the periphery of said cylinderto define a helical passage extending about said cylinder and means fordelivering a fluid under pressure through said duct.
 8. Apparatus asdefined in claim 7 wherein said cam is a plate positioned within andfixed to said cylinder at substantially right angles to its axis ofrotation, said plate having a surface which is adapted to rest againstthe cutting blade pivot means in the absence of torque application tosaid cylinder, and a camming surface which engages with said cuttingblade at a location spaced from its pivot axis when said cylinder isrotated.
 9. Apparatus as defined in claim 3 wherein said cam is shapedto effect projection of said cutting blade during a rotation of thecylinder through an angle of about 60*.
 10. Apparatus as defined inclaim 5 wherein said cam is shaped to effect projection of said cuttingblade during a rotation of the cylinder through an angle of about 60*.